A Neural Signature of Anorexia Nervosa in the Ventral Striatal Reward System
ABSTRACT Animal studies assessing mechanisms of self-starvation under conditions of stress and diet suggest a pivotal role for the mesolimbic reward system in the maintenance of core symptoms in anorexia nervosa, which is corroborated by initial empirical evidence in human studies. The authors examined activity in the ventral striatal system in response to disease-specific stimuli in women with acute anorexia nervosa.
Participants were 14 women with acute anorexia nervosa and 14 matched healthy comparison women who underwent functional magnetic resonance imaging (fMRI) during evaluation of visual stimuli depicting a female body with underweight, normal weight, and overweight canonical whole-body features according to standardized body mass indices. Participants were required to process each stimulus in a self-referring way. Ratings for each weight category were used as the control task.
Behaviorally, women with anorexia nervosa provided significantly higher positive ratings in response to underweight stimuli than in response to normal-weight stimuli, while healthy comparison women showed greater preference for normal-weight stimuli relative to underweight stimuli. Functionally, ventral striatal activity demonstrated a highly significant group-by-stimulus interaction for underweight and normal-weight stimuli. In women with anorexia nervosa, activation was higher during processing of underweight stimuli compared with normal-weight stimuli. The reverse pattern was observed in healthy comparison women.
These findings are consistent with predictions in animal studies of the pivotal role of the human reward system in anorexia nervosa and thus support theories of starvation dependence in maintenance of the disorder.
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ABSTRACT: Objective. In Romania medical-legal studies on the pattern of drug consumption have not yet been conducted nationwide; the purpose of this study was, therefore, to determine whether such a pattern could be identified. Methods. A total number of 577 analyses were performed during a three-year period on people suspected of non-lethal substance abuse, in more than two-thirds of the counties in Romania. Preliminary tests were conducted using immunoassay tests (blood or urine) and confirmatory tests were carried out using either GC-MS or HPLC. Results. 240 cases (41.6%) were negative while 327 cases (58.4%) tested positive for illegal drugs, central nervous system medication or both. Men represented 89.5% of all cases, while women accounted for only 10.5%. The pattern of substance abuse varied significantly, depending on the geographical area. In most cases, the identified drugs of abuse were cannabinoids and opiates, with a significantly different distribution of cases, depending on the geographical area. The highest number of positive cases was identified in the month of October, whereas the smallest numbers were identified in July and December. The annual trend of consumption revealed a significant decrease in the analysed substances in 2011. Conclusions. Our study has determined the presence of a specific pattern of consumption in different geographical areas - a result that suggests the need for more targeted prevention programmes, addressing local particularities in consumption behaviours. A significant decrease in the identification of drugs of abuse in the third year of our study, combined with data attesting the significant increase in the consumption of legal highs suggests that the forensic toxicology laboratories need to be equipped with apparatus able to detect these newer substances of abuse more efficiently.Heroin Addiction and Related Clinical Problems 01/2014; 16(3):7-13. · 0.35 Impact Factor
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ABSTRACT: Empirical evidence suggests abnormalities in the processing of body stimuli in bulimia nervosa (BN). This study investigated central markers of processing body stimuli by means of event-related potentials in BN. EEG was recorded from 20 women with BN and 20 matched healthy controls while watching and evaluating underweight, normal and overweight female body pictures. Bulimics evaluated underweight bodies as less unpleasant and overweight bodies as bigger and more arousing. A higher P2 to overweight stimuli occurred in BN only. In contrast to controls, no N2 increase to underweight bodies was observed in BN. P3 was modulated by stimulus category only in healthy controls; late slow waves to underweight bodies were more pronounced in both groups. P2 amplitudes to overweight stimuli were correlated with drive for thinness and body dissatisfaction. We present novel support for altered perceptual and cognitive-affective processing of body images in BN on the subjective and electrophysiological level. Copyright © 2015. Published by Elsevier B.V.Biological psychology 03/2015; 108. DOI:10.1016/j.biopsycho.2015.03.013 · 3.47 Impact Factor
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ABSTRACT: This focussed narrative review examines neurobiological and psychophysiological evidence supporting a role for altered reward processes in the development and maintenance of anorexia nervosa (AN). In AN, there does not appear to be a generalised inability to experience reward. Rather, data suggest that a reluctance to gain weight leads to an aversive appraisal of food- and taste-related stimuli. As a result, cues compatible with this aberrant mode of thinking become rewarding for the individual. Evidence also suggests that attribution of motivational salience to such cues promotes anorectic behaviours. These findings are consistent with models in which interactions between cognition and reward are important in eliciting the anorectic "habit". A model is proposed which is consistent with elements of other theoretical frameworks, but differs in that its emphasis is towards neural overlaps between AN and addiction. It is consistent with AN being a reward-based learned behaviour in which aberrant cognitions related to eating and shape alter functioning of central reward systems. It proposes that the primary neural problem responsible for the development, maintenance, and treatment resistance is centred in the striatal reward system. This helps shift the emphasis of aetiological models towards reward processing, particularly in the context of illness-compatible cues. Furthermore, it suggests that continuing to explore the utility and valued nature of AN in the patient's life would be a useful inclusion in treatment and prevention models. Copyright © 2015. Published by Elsevier Ltd.Neuroscience & Biobehavioral Reviews 02/2015; 52. DOI:10.1016/j.neubiorev.2015.02.012 · 10.28 Impact Factor